1. Technical Field
The present invention relates to a liquid ejecting apparatus such as an ink jet printer and an ejection inspecting method. More particularly, the invention relates to a liquid ejecting apparatus having a liquid ejecting head supplying a driving signal to operate an ejection driving portion, thereby causing liquid drops to be ejected from nozzle openings, and an ejection inspecting method thereof.
2. Related Art
For example, a liquid ejecting apparatus is an apparatus, that has a liquid ejecting head capable of ejecting liquid, for ejecting various types of liquid from the liquid ejecting head. A typical example of the liquid ejecting apparatus is an image recording apparatus such as an ink jet printer (hereinafter, simply referred to as a printer) that includes an ink jet recording head (hereinafter, simply referred to as a recording head) as the liquid ejecting head and ejects liquid ink from the nozzle openings of the recording head so as to land on a recording medium (ejection target material) such as a recording sheet, thereby performing the recording of an image and the like. In recent years, the liquid ejecting apparatus is also used for various manufacturing apparatuses such as an apparatus for manufacturing color filters of a liquid crystal display and the like, without being limited to the image recording apparatus.
For example, in the above-described printer, when ink is not ejected from any of the plurality of nozzle openings, namely, a so-called missing dot phenomenon occurs, images cannot be printed properly on the recording medium. A technique has already been proposed for inspecting whether or not ink was correctly ejected from all the nozzle openings. For example, JP-A-2008-168526 discloses a technique that causes ink to be electrically charged, allows the charged ink to fly between electrodes, and detects a change in voltage between the electrodes, thereby inspecting whether or not the ink was ejected.
However, it is difficult with the above-described technique to have one shot of ink charged with a sufficient amount of electricity, and hence, there are concerns with the low detection signal level. For this reason, it is difficult to inspect missing dots with a sufficiently high degree of accuracy.
A high detection level can be obtained by having ejecting ink several times from one nozzle opening. However, in doing so, the amount of the ink consumed for the ejection inspection process will increase.